Self-locking switch



' 1,624, 82 Apnl 1927' e. H. WHITTINGHAM 8 SELF LOCKING SWITCH Filed Jan. 11, 1924 Patented Apr. 12, 1927.

UNITED STATES 1,624,882 PATENT OFFICE.

GEORGE H. WHITTINGHAM, 0F BALTIMORE, MARYLAND, ASSIGNOR TO MONITOR CON- TROLLER COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

snLr-rooxme swrrcn;

Application filed January 11, 1924. Serial No. 685,612.

This invention relates to a selflocking switch adapted to be closed and released by electromagnets controlled by push button switches from distant points. The purpose of the invention is to provide a switch of this character with looking and releasing means which will be as free from friction as possible, which will be certain in its action, and in which the circuits of the magnets will be quickly made and broken without burning at the contact surfaces.

In carrying out the invention, I provide a switch, one member of which is biased toward open position, a magnet for closing the switch, and a latch which is hinged to said member and which rides upon a roller while the switch member is moving to and from closed position. When the switch is closed, the latch drops off of the roller and abuts against it, the roller serving as a stop for the latch to hold the switch in closed position; In dropping off of the roller, the latch opens the circuit of the switch-closing magnet, and the closure of the switch makes up the circuit of atripping magnet. \Vhen the tripping magnet is energized, it lifts the latch out of locking engagement with the roller. This releases the movable switch member, which then opens the circuit of the releasing magnet and causes the latch to ride upon the roller in engagement with a contact member which makes up the circuit of the magnet for closing the switch. A. momentary depression of one push button will cause the closure of theswitch, and a momentary depression of the other push button will cause the switch to be opened.

In the accompanying drawing,

Fig. l is a diagrammatic view illustrating the invention with the switch in open position; and,

Fig. 2 is a similar viewshowing the switch closed.

Referring to the drawing, L and L represent the line or supply wires leading from a suitable current source, and 1 represents lamps or other translating devices which are adapted to be connected in circuit with the supply wires through the switch S. This switch comprises a stationary contact 2 and a movable contact. member 3, which is sup ported upon and insulated from one arm of a centrally pivoted switch leverfl. The contact member 3 is connected to the translatin'g devices by a conductor 5, and when the member 3 engages the contact 2, current will flow through said devices. \Vhen the switch is open, the supply of current to the said devices will be cut oil'. A spring 6 normally tends to hold the switch in open position and a magnet 7 is provided for moving the lever 4t against the action of the spring to cause the closure of the switch. A latch 8 is hinged at one end to the upper end of the lever 4, and the opposite end of said latch is turned upwardly, as shown at 8. This latch rests upon a stationary roller 9 when the switch is in open position, as shown in Fig. 1, and when the switch lever moved to closed position, the latch drops by gravity behind the roller, as shown in Fig. 2, and then rests upon a stop 10. The body portion of the latch, in the closed position of the switch, extends from the end of the switch lever to a point below the axis of the roller 9 and effectively locks the switch in closed position.

The latch member 8 is provided with a contact member 11, preferably a block of carbon, which is engaged by a springpressed contact member 12 when the latch is resting upon the roller. This contact member comprises a strip'of'flat metal pivoted at 13, adjacent the magnet and extending over the latch, its free end being adapted to engage the carbon contact on'the latch. A spring 14 constantly presses the contact member toward the latch, and a stop 15 is provided for limiting the downward move ment of said member. When the lever l moved to close the switch S, the carbon contact member 11 makes a rubbing contact with the member 12 until the switch is closed. At this point, the latch drops behind the roller 9 and the carbon contact leaves the spring-pressed member 12, as shown in 2.

A circuit for the magnet 7 extends by conductor 16 through a normally open push button switch 17 to' the coil of the magnet, and thence to the spring arm 12; thence through contact 11, latch 8, lever land conductor 16 to the supply wire L. lVhen the push button switch 17 is momentarily closed, the magnet becomes energized and the switch lever 4 is operated by the magnet to close the switch S. During this closing movement of the switch, the latch is moved from the position shown in Fig. 1 to the position shown in Fig. 2, and at the end of this movement, the contact 11 of the latch drops out of engagement with the spring arm 12 and interrupts the circuit of the magnet 7. The pressure of the arm 12 against the contacton the latch tends to give the latch a quick downward movement, and therefore a quick opening of the magnet circuit, when the end of the latch drops behind the roller. The latch will lock the switch S in closed position and the trans lating devices will receive current until the latch is released.

in order to release the latch from a distant point. I provide an elretro-magnetic tripping device comprising a solenoid it}. having a core 18. upon which is axially mounted a non-magnetic rod if), which extends urnvardlv beneath the free end of the latch. When the solenoid is energized. if the latch is in the locking position shown in Fig. the pin 19 wil kick the free end of the latch above the line joining the pivotal axis of the leve and the pivotal axis ot the roller, and the spring (3 will then rock the lever l: to open the switch S and project the latch over the roller 9, During this movement of the latch, the contact 11 on the latch will engage the spring arm 12 and raise the latter from the stop 15, and the circuit of the magnet 17 will be restored at the points between the latch and the spring arm. The circuit for the solenoid 18 extends from the line wire L by conductor 20 through a normally open push button switch 21 to the solenoid coil, and thence by conductors 22 and 5 to the movable switch member 3, and thence through contact 2 to the supply wire L. hen the switch 21 is momentarily closed, assuming the main switch S to be closed, the solenoid will be energized and its core will cause the latch to be tripped and the switch S will then be moved to open posit-ion by the spring 6. iVhen the switch S opens, the circuit through the solenoid will be interrupted at said switch.

It will be evident from the foregoing decription that when it is desired to close the circuit through the translating devices, the push button 17 will be depressed. The magnet 7 will then cause the switch to close and the latch will lock the switch in closed position, and the circuit of the magnet will also be broken. \Vhen it is desired to cut off the current from the translating devices, the push button switch 21 will be depressed and this will energize the solenoid, which will cause the latch to be tripped and the switch S will open, cutting off the current to the translating devices and also to the solenoid core, It is to be noted that. in making and breaking the circuit of the magnet 7. the the carbon contact on the latch has a sliding movement against the member 12 so that the surfaces will always be keptclean and smooth. The roller 9 constitutes a stop which co-operates with the latch to keep the switch closed. As the roller turns freely, it offers practically no frictional resistance to the operation of the latch in the opening or closing movements of the switch.

hat I claim is:

1. A self-locking switch comprising a switch arm, biased toward open position, a magnet for moving the arm to closed position, a roller, constituting a stop, a latch hinged to the arm and adapted to ride on the roller when the arm is moving to and from open position and to drop oil the roller and abut against the same when the switch is closed, and an electric circuit adapted to be opened by the latch when it drops from the roller.

2. A self-locking switch comprising a switch arm, biased toward open position, a magnet for moving the arm to closed position, a roller, constituting a stop, a latch hinged to the arm and adapted to ride on the roller when the arm is moving to and from open position and to drop off the .roller and abut against the same when the switch is closed, and a circuit for the magnet adapted to be opened by the latch when it drops from the roller.

3. A self-locking switch comprising a switch arm, biased toward open position, a magnet for moving the arm to closed position, a roller, constituting a stop, and a latch hinged to the arm and adapted to ride on the roller when the arm is moving to and from open position and to drop oit the roller and abut against the same when the switch is closed, said latch having a contact surface, a contact member adapted to be engaged by said surface when the latch is upon the roller and to become disengaged therefrom when the latch drops otf the roller. and a circuit for the magnet including said surface and member.

4. A self-locking switch comprising a switch arm, biased toward open position, a magnet for moving the arm to closed position, a roller, constituting a stop, a latch hinged to the arm and adapted to ride on the roller when the arm is moving to and from open position and to drop off the roller and abut against the same when the switch is closed, said latch having a contact surface, a yielding contact member extending longitudinally of the latch adapted to be engaged by said surface when the latch is upon the roller and to become disengaged therefrom when the latch drops oil" the roller, and a circuit for the magnet including said surface and member.

5. A self-locking switch comprising a switch arm biased toward open position, a magnet for moving the arm to closed position, a roller, constituting a stop, a latch hinged to the arm and adapted to ride on the roller when the arm is moving to and inn from open position and to drop OR the roller and abut against the same when the switch is closed, to lock the same, an electric circuit adapted to be opened by the latch when it drops from the roller, and an electro-magnetic device for tripping the latch to release the arm.

6. A self-locking switch comprising a switch arm biased toward open position, a magnet for moving the arm to closed posi tion, a roller, consittuting a stop, a latch hinged to the arm and adapted to ride on the roller when the arm is moving to and from open position and to drop off the rolll er and abut against the same when the switch is closed, to lock the arm, a circuit for said magnet adapted to be opened by the latch when it drops from the roller, an electro magnetic device for lifting the latch to release the arm, and a circuit for said device adapted to be opened by the switch when the latter opens.

7. A self-locking switch comprising a switch arm biased toward open position, a magnet for moving the arm to closed position, a roller, constituting a stop, a latch hinged to the arm and adapted to ride on the roller when the arm is moving to and from open position and to drop off the roller and abut against the same when the switch is closed, to lock the arm, an electric circuit adapted to be opened by the latch when it drops from the roller, an electromagnetic device for tripping the latch to release the arm, and a circuit for said device adapted to be opened by the arm when the latter is released.

8. A self-locking switch comprising a switch arm, biased toward open position, a stop, a latch hinged to the arm and adapted to ride on the stop when the arm is moving to and from open position and to drop off the stop and abut against the same when the switch is closed, an electric circuit adapted to be opened by the latch when it drops from the stop, and an electromagnetic device for tripping the latch to release the arm.

9. A self-locking switch comprising a switch arm, biased toward open position, a stop, a latch hinged to the arm and adapted to ride on the stop when the arm is moving to and from open position and to drop off the stop and abut against the same when the switch is closed, a magnet for moving the arm to closed position, a carbon contact on the arm and a yielding contact-member extending longitudinally of the latch adapted to be engaged by said contact when the latch is on the stop and to become disen gaged therefrom when the latch drops oil the stop, and a circuit for the magnet including said contact and member.

In testimony whereof I hereunto aflix my signature.

GEORGE H. WHITTINGHAM. 

